Earth furrowing apparatus



Jan. 18, 1955 D. L. SHELTON 2,699,715

EARTH FURROWING APPARATUS Filed Feb. 8, 1949 V 5 Sheets-Sheet l l ymwi wATT'OR N EY Jan. 18, 1955 o. L. SHELTON 2,699,715

EARTH FURROWING APPAIRATUS A 1. .SHEL TON ATTORNEY Jan. 18, 1955 FiledFeb. 8, 1949 D. L. SHELTON EARTH FURROWING APPARATUS 5 Sheets-Sheet 3 D.L GHELTO/Y kmz ATTOR N EY Jan. 18, 1955 D. L. SHELTON EARTH FURROWINGAPPARATUS 5 Sheets-Sheet 4 Filed Feb. 8, 1949 ATTOR N EYE,

Jan. 18, 1955 D. L. SHELTON EARTH FURROWING APPARATUS 5 Sheets-Sheet 5Filed Feb. 8. 1949 ATTQR N EYs United States Patent EARTH FURROWINGAPPARATUS Dothan L. Shelton, Amarillo, Tex.

Application February 8, 1949, Serial No. 75,185

13 Claims. (Cl. 97--198.1)

This invention relates to an earth-furrowing apparatus.

Various types of chisel tool apparatus for earth furrowing have been inuse for many years, such implements involving forwardly and downwardlyinclined furrowlng tools carried by the lower ends of shanks havlngtheir upper ends fixed with relation to the frames of the mplements.Such types of apparatus have been sub ect to numerous disadvantages,particularly where usedm rocky soil. For example, the shanks have beenso r1g1d ly connected to the frames that substantial forces transmittedto the frames upon the encountering of stones and rocks have haddestructive bending effects on the frames or shanks, or both, with theresult that such implements often have one or more furrowing toolsarranged a substantial distance above the remaining tools, andfrequently actually above the surface of the earth.

Moreover, unavoidable inaccuracies in manufacture in an apparatus ofthis character are such that most implements of this character vary asto the depth of penetration of the furrowing tools into the ground asmuch as two or three inches, there usually being no means for 1nd1-vidually adjusting the tools as to the depth of penetration. The shanksfor the tools being almost necessarily formed of spring steel, it isimpracticable to bend the shanks to provide for uniform earthpenetration of the tools, and if this is done, damage due to strains onthe parts d1sturbs the uniformity of such crude means of adjustment.

It has been proposed to relieve torsional strains on the tool-carryingframe members by interposing some resilient means to absorb shocks andstrains. For example, it has been proposed to provide a coil in themetal of each shank in the horizontal portion thereof, and it furtherhas been proposed to pivot the shanks to the frames and oppose pivotingmovement by spring means. Devices of this character have been found tobe unsatisfactory for the reason that they permit lateral swinging ofthe furrowing tools with the result that the tools can swing aroundinstead of uprooting thickly rooted clods of earth.

In a certain earlier type of apparatus of this character, it was foundthat the furrowing tools were self-sharpening, being provided with awhetting action due to the particular oscillatory motion of thefurrowing tool. This result occurs when the design and proportions ofthe parts are such that the flexing of the lower part of the shanktending to move the tool downwardly is substantially compensated for bythe tendency of the upper portion of the shank to flex upwardly. Undersuch conditions, the oscillatory movement is such that the leading edgeof the furrowing tool moves back and forth substantially horizontally.Such an arrangement is not only advantageous because of theself-sharpening feature, but the flexing of the shank as distinguishedfrom the use of a rigid shank requires substantially less power forpulling the implement forwardly. Such prior devices, however, do notprovide for sufficient flexing of the shank when encountering a stone ofsubstantial size so as to permit the tool to rise and pass over the topof the stone.

in earlier types of apparatus, moreover, unsatisfactory means have beenprovided for elevating the earth-working tools out of contact with theground when desired. Where such elevating means has been manuallyoperable, an operator must leave his seat on the tractor in order tooperate the manual means in a satisfactory manner. Where the elevatingmeans is purely hydraulic, subject to control by the operator withoutleaving the tractor, the hydraulic means cannot be operated and thetools raised from the ground except when a source of hydraulic pressureis available.

An important object of the present invention is to provide a novel beamstructure for agricultural implements, which is quite simple inconstruction and economical to manufacture and which is highly effectiveas the means, for drawing earth-working tools over and through the soil.

A further object of the present invention is to provide a novelagricultural implement wherein the supporting means for the shanks ofthe earth-working tools is such as to substantially eliminate anypossibility of damage to the frame of the implement incident to severestrains, for example, when striking large stones or rocks.

A further object is to provide a novel supporting frame structure andassociated elements which is of such type as to increase the degree offlexibility of the shank of an earth-working tool without increasing thelength of the shank rearwardly of the supporting means and without theuse of cushioning springs of any type.

A further object is to provide such an apparatus wherein thesubstantially increased flexing action of the tool shanks isaccomplished without permitting any greater degree of lateral movementof the furrowing tools than is true or" the use of the same type ofshanks with conventional supporting means therefor.

A further object is to provide a novel type of supporting frame incombination with an earth-working tool whereby torsional strains on theframe are substantially reduced and the frame is provided with increasedability to withstand the torsional strains to which it is subjected,thereby lengthening the normal fatigue life of the parts and reducing oreliminating repair bills and the loss of the use of the implement whileit is being repaired.

A further object is to provide an implement of this character wherein ahighly novel type of adjusting means is provided for each earth-workingtool whereby such tools are subject to quick and easy adjustment wherebyuniform earth penetration is effected.

A further object is to provide an apparatus of the character justreferred to wherein the novel characteristics of the adjusting means aresuch that the adjustment-setting means is subject to substantiallynegligible strains under forces transmitted thereto in the use of theimplement, whereby the implements may be easily caused to remain inproper desired adjusted positions.

A further object is to provide an apparatus of this character whichreadily lends itself to the use in connection therewith of sub-soilshanks whereby the advantageous results referred to above can be securedwhile tilling the soil to a depth of twelve inches or more.

A further object is to provide a novel combined hydraulic and manualelevating means for the tools whereby the earth-working tools may beraised hydraulically or manually, depending upon circumstances, whollywithin the choice of the operator.

Other objects and advantages of the invention will be come apparentduring the course of the following descnption.

In the drawings, I have shown two embodiments of the invention. In thisshowing,

F gure 1 is a perspective view of the apparatus,

Figure 2 is an enlarged detailed sectional view on line 22 of Figure 1,illustrating the flexing of a tool shank when passing over a large stoneor other obstruction,

Figure 3 is a similar view taken transversely through the entiresupporting frame showing a plurality of the tools and shanks in normalpositions,

Figure 4 is an exploded perspective view of one of the shank-adjustingmeans and associated elements.

Figure 5 is a view similar to Figure 2 diagrammatically representing acomparison between the oscillatory action of a shank of the presentapparatus as compared with other conventional shanks,

Figure 6 is a substantially enlarged sectional view taken substantiallyon line 6-6 of Figure 1,

Figure 7 is a view taken substantially on the same plane as Figure 6,showing the invention employing a sub-soil furrowing shank and tool,

Figure 8 is a sectional view generally similar to Figure 3 2,diagrammatically representing the action occurring through thegeneration of certain lines of force in the apparatus, and

Figure-9 is a side elevation of portions of the apparatus particularlyillustrating the tool-elevating means, parts being broken away-and partsbeing shown in section.

Referring to thedrawings, and particularly Figures 1 and- 3, the'numeral10--designa-tes the frameof the implement as a a whole, shown in thepresent instance as comprising a pair of end-'frame members 11, forwardand rear frame members 12, and an intermediate transverse-frame member13 preferably equidistantly spaced from'the. members 12. Inner framemembers 14, spaced from and-parallel to themembers 11, extend betweenand are preferably welded to the members 12. The intermediate member 13is'welded at its ends to the members 14. Wheels 16 for supporting theimplement are arranged in the spaces provided between the framemembers-11 and 14 as shownin Figure l, and are journaled' withrespect tothe frame in a manner to be-described.

The frame members 11 and 14 may be of any desired cross section,andpreferably are of channeled section. The frame members 12 and 13 areof inverted angle section preferably of a particular form described indetail below and clearly shown in Figures 2, 3, 5, 6 and 7. The framemembers 12 and 13 are the implementcarrying members and they may be, andpreferably are, rigidly braced relative to each other by a central framemember. 18 which may be of .any desired cross sectional shape and ispreferably notched to fit the frame member 13. The member 18 is rigidlywelded to the frame members 12 and 13. A draft connection 20, which maybe of any desired shape, is preferably boltedzio the frame member 18 andis suitably braced as at A plurality of earth-furrowing units isconnected to each of the frame members 12 and 13. These units beingidentical, only one need be referred to in detail. Similarly, only oneof the frame members 12 or 13 need be described in detail since they areidentical. These frame members are of inverted angle cross-section'andinclude a dowwnardly and forwardly extending flange and a downwardly andrearwardly extending flange 26. Particular attention is invited to thefact that the lower edge of the flange 25 terminates a substantialdistance above the lower edge of the flange 26. Each of the furrowingunits comprises a shank indicated as a whole by the numeral 28 and isanchored with respect to the adjacent framemember 12 or 13 by bracketmeans indicated as a whole by the numeral 29 and forming one of theimportant features of the present invention.

Each of the. bracket means-29 (Figures 4 and 6) comprises a plate 32adapted to seat against the lower edges of the flanges 25 and 26, and istherefore inclined upwardly toward the front end of the apparatus. Theforward edge of each plate 32 extends beyond the flange 25 and isapertured as at 33 to receive the ends of angle bolts 34. The lower endof each plate 32 has opposite side portions 36 bent to assume asubstantially horizontal position. These portions or lips of the plate32 are apertured as at 37 to receive the other ends of the bolts 34,these bolts being attached to clamp the plate'32 in position byconventional nuts 38 in a manner further referred to below.

Intermediate thelips 36, the plate 32 has its lower rear end extendingrearwardly beyond the edge of the flange 26, as at 40, and bent intosubstantially arcuate form. Each tool-carrying shank has a horizontalportion 41 extending beneath and in contact with the plate portion 40,the latter acting as a bearing face for the shank 41, as describedbelow. An attaching strap 44 (Figure 4) has its intermediate portion 45offset downwardly for the passage of the shank 41 therethrough. The endsof the strap 44 are apertured, as at 46, for the extension therethroughof the bolts 34, the adjacent nuts 38 serving to clamp the ends of thestrap 44 against the plate portions 36 and to fix the position of theshank 41.

Each plate 32 carries depending spaced flanges 50, the space betweenthese flanges being approximately equal to the width of the associatedshank 41 whereby the latter extends between the flanges 50. The forwardend of each shank is attached by a bolt 51 to a block 52 lying beneaththe end of the shank. The block 52 is apertured as at 53 to receive abolt 54 which extends through slots 55 formed in 55 preferably arearranged at a angle to the vertical and horizontal for a purpose to bedescribed. As will become apparent, the bolt 54 may be loosened andmoved longitudinally in the slot to adjust the position of the shank 41to vary the adjustment of the furrowing tool to be referred to.

As previously stated, each shank 28 has an upper horizontal portionclamped relative to one of the frame members 12 or 13. Rearwardly of thestraight portion 41, each shank is provided with a downwardly curvedportion 60, usually arcuate in shape and provided at its lower end witha furrowing tool 61. In practice, it is preferred that the shanks 28. beformed of A" by 2" spring steel and that the portion of each shank beformed as an arc of a circle having a radius of approximately 9". Undersuch conditions, the length of the straight shank portion '41 of eachfurrowing unit rearwardly of its associated clamping saddle 44 will beapproximately 8 and the .length of the curved portion 66 preferably willbe between 22 and 24".

With the shanks 28 formed in accordance with the preferred proportionsreferred to, it has been found that the tools 61 will beself-sharpening. Referring to Figure 5, I have diagrammaticallyrepresented two other furrowing units represented respectively by theletters A and B from which a comparison of the operation of the presentfurrowing units can be obtained. With the shanks of such-units formed asdescribed, the encountering of resistance as the tool 61 moves throughthe ground causes the. shank 28 to flex. This flexing tends to increasethe radius of the curved portion 60, and this flexing, in itself, wouldcause the point 62 of the tool 61 to move downwardly. However, theflexing forces cause each straight shank portion 41 to be distorted fromits straight shape into an upward and rearward curve tending to lift thepoint 62. With properly proportioned shank portions,- for example asdescribed, the upward flexing of each shank portion 41 compensates forthe tendency of the shank portion 60 to increase its radius ofcurvature, with the result that the point 62, during oscillatorymovementof the free portion of the shank, moves back and forth in asubstantially straight line as indicated at 63 in Figure 5. With ashorter straight shank portion, or with the elimination of such portion,as is the case with the unit-A in Figure 5, there is no compensationforthe tendency of the curved shank portion to increase its radius ofcurvature, and as a result, the oscillatory movement of the shank-causesthe tool point to move backand forth at anangle to the horizontalapproximately as indicated by the line 64 in Figure 5.

Conversely, in the use-of a straight shank portion longer than the-sh-ank-41, as in the case of the furrowing unit the flanges 50. Theslots B in Figure .5, the upward flexing of the straightshank portion isexcessive with relation to the increasing of the radius of the curved.portion with the result that the tool point moves back and forth assuggested by the line 65 in Figure 5. I

In this connection, it is pointed out that movement of the tool 61through the ground necessarily takes place against resistance regardlessof the presence of stones or other obstructions. Resistance to forwardmovement of the point 62 causes it to'move horizontally rearwardly alongthe line 63 until the increased resistance to bending movement of theshank overcomes resistance to the forward movement of the point 62,whereupon such point moves forwardly along the line 63 back to aposition at or adjacent its normal position, pending the building up offurther resistance to forward movement. This ac tion is repeatedcontinuously during operation of the implement and the straight back andforth motion of the point 62 along the line 63 continuously whets thepoint 62 and maintains it in sharp condition.

The shanks A and B are disadvantageous for two reasons. The oscillatorymovement causes the tool points to travel angularlywith the result thatthe points are continuously blunted rather than sharpened. Moreover,inthe case of the unit A, resistance to movement of the tool pointcauses the latter to move downwardly and rearwardly relative to theapparatus whereby it digs more deeply into the soil and increasesforward resistance to movement of the .implement. .In the case of theunit .B,

ersistance 'to forward movement causes the tool point to be lifted, andaccordinglythe depth of penetration is substantially reduced once duringeach oscillatory movement. Therefore, the furrowing unit 28 is highlyadvantageous in that it provides foruniform movement of the tool point62 through the ground in the absence of stones and similar obstructions,and the point 62 is self-sharpening.

In spite of the substantial advantage of the propor-.

tioning of the unit 28 rearwardly 44, the extent to which the point inpassing over obstructions such as a stone 65 (Figure 2) withouttransmitting possibly destructive forces to the frame members 12 and 13is limited. If the clamped free end of each shank 41 were maintainedinfiexibly in horizontal position, the tool point, relatively speakingcould swing upwardly only to the height indicated by the line 66 withouttransmitting possibly destructive forces to the frame, whereas in thecase of an obstruction such as the stone 65, it is necessary for thepoint to swing upwardly to the level of the line 67, representing thelevel of the top of the stone 65. i

The mounting of each unit 28 relative to the supporting frame members 12and 13 is such that increased flexibility for passing over obstructionsis provided without appreciably changing the oscillatory action throughwhich are obtained the highly advantageous results described inconnection with Figure 5. Referring to Figure 6, it will be noted that asubstantial portion of the forward end of each shank portion 41 is freeof any clamping means. Accordingly, when the shank portion 41 flexesupwardly as indicated in dotted lines in Figure 6, the portion of theshank lying between the saddle 44 and block 52 is free to flexdownwardly as indicated by the dotted line 70 in Figure 6. Thus, upwardforces flexing the shank portion 41 to the rear of the saddle 44 arepartially absorbed by the downward flexing of the shank as at 70,accordingly relieving the supporting frame of some of the destructiveforces and permitting the tool point 62 (Figure 2) to swing to a higherpoint without damaging the frame members.

In this connection, it is also particularly pointed out that the use ofand 13 is highly effective in reducing the effect of otherwisedestructive forces when the tool points pass over obstacles ofsubstantial size. Each curved plate portion 40 (Figure 6) constitutes abearing through which upward thrusts of the shank 41 are transmitted tothe frame members. Such thrusts generate torque in the frame members,and the center of torque is approximately at the point 75. Forces aretransmitted to the bearing 40 on a line perpendicular to the straightshank portion 41. With such shank portion horizontal, as shown in solidlines in Figure 6, upward forces on the bearing 40 would be vertical, asindicated by the line 76. This line is at an acute angle to the frameflange 26. As the shank portion 41 is flexed upwardly, the upwardlyexerted line of force, perpendicular to the point of contact of theshank portion 41 with the bearing 40, swings toward the right as viewedin Figure 6, as indicated, for example, by line 77.

It will be apparent that the upwardly exerted forces, as they increase,move progressively closer to the center of torque as indicated by thenumeral 75. Therefore, as these forces increase in passing overrelatively large obstacles, the movement of the lines of force upwardlyagainst the bearing 40 move progressively closer to the torque center 75and more nearly parallel to the flange 26 of the frame member 13, thustending relatively to reduce the torque on the frame members. Thus thetransmission of destructive forces to the frame members is minimized.The construction shown in detail in Figure 6, therefore, is highlyadvantageous for the reasons stated.

In Figure 7 of the drawings, I have shown a modified. form of theinvention in the nature of a chisel type sub-soil plow. For many years,manufacturers have sought to devise a satisfactory sub-soil shank, thatis, a flexible shank which will support a tillage point to plow atdepths of 12 or more. A flexible shank is desirable for the reason thatit can be pulled through the ground with considerably less power than isrequired for the conventional rigid shank.

These efforts have not been crowned with particular success. Thestandard chisel plow shank is curved on the radius of 9" and experiencehas shown that this radius will plow more efiiciently at depthsnotexceeding 9", that is, to a point where a tangent to the curved shankat the ground level is approximately vertical.

of the clamping saddle 62 can swing upwardly the inverted angle framemembers 12 Under such conditions, the soil, as it is broken loose inplowing, rolls up the shank and sheds off approximately at the groundlevel, freely passing around and behind the shank. If the shank is moveddownwardly to plow to a greater depth, for example an additional 4", thelevel of the ground is above the center of curvature of the shank, thuscausing the dirt to move forwardly above the center of curvature of theshank. Thus the portion of the shank above center is performingsubstantial work, and much greater tractive power is required. Plowingat such a depth with a device of this character creates a dead space inthe shank that will not shed the dirt and, i1} actual practice, this atleast doubles the draft of the p ow.

It would appear obvious that the answer to this problem would be tobuild a shank on a 12" radius, assuming that plowing is to be done at adepth of 12". This has proved wholly unsatisfactory. As previouslystated, certain relative dimensions must be observed in order tomaintain the proper oscillatory action of the shank. A shank curved on a12" radius would require at least 8" of free horizontal shank in orderto retain the proper oscillatory action, and the curved section would beapproximately 33'? in length. This would provide a total length of 41"of free flexing shank as compared with a total length of 30 or 31 forthe standard shank. To get the proper action from such a shank curved ona 12" radius would require that the weight of the stock from which it isfabricated be increased by approximately seventy per cent. The shanksare made of spring steel, as stated, which is relatively expensive, andthe use of heavier shanks would add materially to the manufacturingcosts. Moreover, such a shank would further require that the framemembers supporting the shank be spaced several inches further apart inorder to give the clearance necessary for the proper flexing action asillustrated in and described in connection with Figure 6.

The problems referred to are completely overcome with the arrangementshown in Figure 7. The shank shown in Figure -7 is made from the same oronly slightly heavier stock than the shanks described above,.beingpreferably 1 by 2 in cross section. Referring to Figure 7, the shank asa whole is indicated by the numeral 85 and has a horizontal forwardportion 86 mounted in the same manner as the shank described above, thesupporting elements being designated by the same reference numerals asbefore. The free portion of the shank 85 is bent on two separate curvesof different diameters. The lower portion 87 of the shank has its centerof curvature located at the point 88, the portion 87 being curvedpreferably on a 9 radius. The upper free shank portion 89 has its centerof curvature approximately at the point 90, the radius of curvaturepreferably being 15'. The centers 83 and 90 are preferably in the samehorizontal plane, and the point 90 is preferably arranged verticallybeneath the bearing point of the: shank against the bearing 40.

The lower portion 37 of the shank, in operation, will flex downwardlywhile the portion 89 of the shank will flex upwardly. In the form of theinvention previously described, the ratio of the shank portion below thecen ter line to the shank portion above the center line is approximately2:5. Actual preferred dimensions of the first-described form of shankare about 9" of shank below the center of curvature and 14" of curvedand of horizontal shank above the center of curvature, a total of 22".These dimensions relate to the free flexing shank rearward of the frameattaching means. The subsoil shank illustrated in Figure 7 substantiallyretains these portions. This shank is formed with 9" of curved sectionbelow the center of curvature and 23" above, or a ratio approximating3:8. By forming the upper 23 of this shank on a curve having a 15"radius with the lower 9" of shank curved on a 9" radius, the shank willretain the proper oscillatory characteristics described above and willplow from 12" to 14" deep with a minimum of draft.

In operation, the shorter curvature of the lower shank section 87 willovercome any tendency for the more gradually curved upper section toroll or move the dirt forwardly. This characteristic keeps the shankactive and prevents its becoming a dead pull as in the case of thestandard shank set to plow deeper than the intended depth. This shortercurvature of the shank section 87 conforms to the curvature of standardtillage points and gives the points the proper pitch to cause them totake the ground. Because of the length and special relative curvaturesof the free shank portions, it can be used on any frame that will carrythe standard shank. Employed with the shank mounting as described above,it possesses the highly desirable characteristics of the shank 28.

There is described above in connection with Figures 4, and 6, the meansfor adjusting the free length of the shank. The same adjusting means isemployed in connection with the form of the invention shown in Figure 7.The advantages 'of the adjusting means will be apparent from aconsideration of Figure 8. The arrangement of parts is such that endwiseslipping of the horizontal shank portion is prevented when the implementis in use. When the plow is in motion, the frame member 12 is moved in aforward direction as indicated by the arrow 95. Engagement of thefurrowing tool 61 with the ground will exert a force against said toolin the opposite direction as indicated by the arrow 96. This transmitshorizontal forces to the frame member 12 as indicated by the arrow 97and at the same time transmits a clockwise torque to the frame member 12as indicated by the arrow 98; Since the shank 41 tends to pivot on thebearing 40, it will be apparent that the forward end of the shank tendsto swing downwardly as in dicated by the arrow 99. The combination ofthe two lines of forces represented by the lines 97 and 99 produce aresultant moment downwardly and rearwardly as indicated by the arrow100. This line 100 therefore roughly indicates the direction of forcesacting on the bolt 54 when the plow is in use. The slot 55 is at asubstantial angle to the line of force 100, and preferably at an angleof 90 .to such line of force; The tendency, therefore, is

for the bolt 54 to bear against the sides of the slot 55 rather than totend to move longitudinally of the slot.

It has been found in practice, therefore, that the parts will remain inadjusted position with relatively slight glalmging forces exerted by thehead and nut of the In Figure 9, I have illustrated a novel depthcontrol and power lift mechanism for the earth-working tools. Two ofthese devices, one for each side of the apparatus, are employed as shownin Figure 1. The supporting 'wheels 16 of the apparatus are supportedrespectively on spindles 110, each of which is carried by the free endof an arm 111, the other end of which is supported by a shaft 112extending between and fixed to the adjacent frame members 11. and 14(Figure 1). The shaft 112 also rotatably supports a pair of spacedupwardly extending arms 114 between the upper ends of which is arrangeda crosshead 115 supported in rocking engagement with the arms 114 bysuitable trunnions 116.

screw shaft 118 is threaded in the crosshead 115 and has its rear endportion rotatable in a crosshead 119. This crosshead is supported bytrunnions 120 between the upper ends of stationary arms 121 fixed to theframe members 14 by bolts 122. Collars 123 on the shaft 118 preventlongitudinal movement of the screw shaft 118 relative to the crosshead119, and the screw shaft is provided with an operating crank 124. Itwill become apparent that rotation of the screw shaft 118 will rock thearms 114, which action will relatively move the parts so that the arms111 swing relatively downwardly about the axis of the shaft 112. Suchmovement is limited by a foot 128 carried by the lower ends of the arms121.

Adjacent the spindles 110, the arms 111 are provided with upstandingarms 132 rigidly connected to the arms 111. At their upper ends, thearms 132 are pivotally connected as at 133 to the piston rod 134 of apiston 135 arranged in a cylinder 136. This cylinder is provided with ayoke 138-pivotally connected as at 139 to projections 140 carried by thearms 114. Means is provided for limiting movement of the piston 135toward the left as viewed in Figure 9, and to this end, the piston hasbeen shown as being provided with a boss 142 engageable with theadjacent end of the cylinder 136. Hydraulic fluid may be introduced intothe left hand end of the cylinder 136 through a pipe 143.

The pipe 143 leads to thetractor connectedto the present implement andon the tractor there is provided a source of hydraulic fluid pressureand a control valve for connecting such source to thepipe 143. The fluidpressureso'urce and the valve are conventional and have not beenillustrated. With pressure released from the cylinder 136, the piston135 occupies the position shown in Figure 9. Accordingly, it will beapparent that rotation of the screw shaft 118 to move the arms 114forwardly will exert a forward force on arms 132, thus moving thespindle relatively downwardly while moving the frame 10 relativelyupwardly to adjust the depth of the earth-working implements or to liftthem completely from engagement with the ground. To perform the samefunctions while the apparatus is in use, the operator may turn thecontrol valve (not shown) on the tractor, thus forcing the piston towardthe right in Figure 9 to elongate the distance between the pivots 133and 139. When inoperative, the hydraulic motor forms a thrust linkbetween the arms 114 and 132 for manual vertical adjustment of the frameand earth-working tools, this adjustment being possible regardless ofthe connection of the apparatus to a tractor. The apparatus may beoperated from the tractor, as stated, the hydraulic motor ceasing itsfunction as a thrust link and becoming a power source to effect verticaladjustment.

Operation The operation of the apparatus will be apparent from theforegoing description. The inverted angles 12 and 13 provide implementsupporting frame members having the maximum degree of strength inproportion to their weight, and as described, torsional forces areabsorbed much more readily 'by such form of frame than is possible withthe conventional I-beam frame or the like. By making the forward flangesof the angles shorter than the rear flanges, ample space is provided forthe shank-adjusting means. This adjusting means is highly efficient inoperation since, for the reasons stated, thrusts are absorbed laterallyrather than longitudinally of the slots 55 thus rendering it easier tokeep the parts adjusted for any depth of penetration of theearth-working tools into the ground.

As specifically described in connection with Figure 5, the presentinvention permits the maintenance of the proper ratio of the portions ofthe shank 28 to secure the proper oscillatory movement of theearth-working implement, the point of this implement moving back andforth horizontally in normal operation. Thus uniform depth ofpenetration is provided while at the same time reducing the powerrequired for moving the tractor forwardly. However, while providing forthe most effective oscillatory movement of the earth-working tool, theflexibility of each shank is materially increased by spacing the pointof contact of the shank portion 41 with the bearing 40 and the point ofengagement of the forward extremity of the shank'portion 41 with theadjusting block 52. As the shank portion 41 rearwardly of the bearing 40flexes upwardly, the shank portion forwardly of the bearing 40 flexesdownwardly, thus increasing the degree of flexibility of the shank as awhole. The portion of the shank forwardly of the bearing 40 naturallybecomes very slightly elongated as flexing takes place, as indicated bythe numeral 70. The point of contact of the shank 41 with .the bearing40 under such conditions moves slightly to the left as viewed in Figure6, this action being permitted by slight sliding movement of the shank41 in the saddle 44. The increased degree of flexibility provided in themanner stated also permits the point 62 of the earthworking implement topass over taller obstacles such as stones, as illustrated in Figure 2,without undue strains and resultant damaging of the tool shanks or thesup.- porting frames therefor.

The use of the form of the invention shown in Figure 7 is highlydesirable for the reason that it preserves the proper ratio of shankportions to provide the desired oscillatory movement while at the sametime preventing the forward piling of the dirt in the manner described.Thus sub-soil plowing is possible with the same oscillatory action andwithout increasing the power which would otherwise be required forplowing to a greater depth. The mounting of the device in Figure 7relative to the supporting frame is the same as in the other forms ofthe invention, increased flexibility being provided as describedtogether with the provision of the same highly desirable adjustingmeans.

Adjustment of. the shank portions 41 is readily accomplished merely byloosening the bolt 54 and moving it upwardly and rearwardly ordownwardly and forwardly in the associated slots 55. This adjustment isprovidedv primarily so that all of the points of the earth-working toolscan be easily arranged at the same level so that all penetrate the earthto the same depth. impossible to secure of this character.

The depth control and power lift mechanism shown in Figure 9 is highlydesirable for the reason that it ;combines a manual and poweradjustment, whereby the mechanism may be operated under any conditions.Vertical adjustment of the supportingframeto adjust the depth ofpenetration in the ground or to completely lift the earth-working toolsis not limitedto hydraulic operation when a source of hydraulic power isThe operator may turn the two cranks 124 to move the supporting frameverticallyreven when the implement is not connected to a tractor. On theother hand, when the device is connected to a tractor and asource ofhydraulic power is available, vertical adjustment for the completeelevation of the earth-working implements from the ground may be quicklyand readily accomplished by connecting the pipe 143 to the source ofhydrauliopressure. Relative downward swinging movement of the right handend of the arms 111 in Figure 9 is limited by the foot 128 of eachadjusting mechanism.

While the invention has been illustrated and described for use inconnection with an earth-working tool of a particular type, it will beclearly understood that the invention is not limited in its use to anyspecific type of earth-working tool. Quite obviously, the novel invertedangle shaped cross-members may be employed as the means for pulling anytype of earth-working tool or tools.

I claim:

1. An agricultural implement comprising a frame having a tool-supportingmember extending transversely of the direction of movement of theimplement, said member being of inverted V-cross section, anearth-working tool comprising a flexible shank having an upper forwardend substantially horizontally arranged beneath said toolsupportingmember, said tool-supporting member having a downwardly and rearwardlysloping flange and a downwardly and forwardly sloping flange, andseparate means for fixing the forward end of said shank at spaced pointsagainst vertical movement with respect to said flanges, said forward endof the shank between said fixing means being unsupported whereby it isfree to flex.

2. An agricultural implement comprising a frame having a tool-supportingmember extending transversely of the direction of movement of theimplement, said member being of inverted V-cross section, anearth-working tool comprising a flexible shank having an upperforwardend substantially horizontally arranged beneath said toolsupportingmember, said tool-supporting member having a downwardly and rearwardlysloping flange and a downwardly and forwardly sloping flange, means forconnecting said forward end of said shank to said downwardly andrearwardly sloping flange against vertical movement relative thereto,and connecting means forward of said first-named connecting means forfixing said forward end of said shank against vertical movement relativeto said tool-supporting member, said two connecting means being spacedfrom each other and said shank between such connecting means being freeto flex.

3. An implement constructed in accordance with claim 2 wherein thesecond-mentioned connecting means comprises an attaching device securedto said tool-supporting member and provided with an upwardly andrearwardly sloping slot, and a bolt fixed with respect to said forwardend of said shank and projecting through said slot for adjustableconnection to said attaching device.

4. An implement constructed in accordance with claim 2 wherein the loweredge of said downwardly and forwardly sloping flange terminates abovethe level of the other of said flanges, the second-named connectingmeans comprising a pair of ears spaced transversely from each other andspaced forwardly of said first-named connecting means, said forward endof said shank being arranged between said ears and said ears beingprovided with up wardly and rearwardly sloping aligned slots, and anadjusting bolt fixed with respect to said forward end of said shank andprojecting through said slots to be secured in adjusted positionstherein.

5. An earth-working implement comprising a frame having atool-supporting member extending transversely of the direction ofmovement of the implement over the ground, a tool comprising a flexibleshank having a lower rear end adapted to be connected to anearth-working element and having an upper forward substantially hori- Itis practically such adjustment, withpresent devices not available.-

zontal end, and means for fixing the forward end of said shank to saidtool-supportingmember at spaced points against vertical in shank betweensaid spaced points-being unsupported whereby it is free to flex.

6. An earth-working implement comprising a frame having atool-supporting member extending transversely of the direction ofmovement of the implement over the ground, a tool comprising a flexibleshank having a lower rearrend adaptedto be connectd to an earth-workingelement and having an upper forward substantially horizontal end, a pairof spaced attaching means for securing the said forward end of saidshank to said tool-supporting member against vertical movement relativethereto, said shank between said attaching means being free to flex, oneof said attachingmeans comprising a member having a slot thereinarranged at an angle to the horizontal, and a bolt fixed tosaid shankand adjustable in said slot.

7. An earth-Working implement comprising a frame having atool-supporting member extending transversely of thedirection'ofmovement of the implement, said toolsupporting member being of invertedangle section and having a downwardly and forwardly sloping flange and adownwardly and rearwardly sloping flange, a plate secured against thelower edges of said flanges, an earthworking tool comprising a flexibleshank having an upper forward end arranged beneath said tool-supportingmember and said plate, said plate, beneath said downwardly andrearwardly sloping flange, being curved upwardly to provide a bearingsurface: against which the adjacent portion of said shank engages, meansfor maintaining such portion of said shank in engagement with saidbearing surface, and means for connecting the forward end of said shankto said plate at a point spaced forwardly of said bearing surface, saidshank, between said connecting means and said bearing surface, beingfree to flex.

8. An implement constructed in accordance with claim 7 wherein saidconnecting means comprises a pair of depending ears carried by saidplate and provided with aligned slots inclined from the horizontal, anda bolt fixed with respect to the forward end of said shank and extendingthrough said slots for adjustable connection with said ears.

9. An earth-working implement comprising an earthworking tool having aresilient shank adapted to have an earthworking element fixed to thelower end thereof, the lower portion of said shank being curveddownwardly and forwardly approximately about an arc having approximatelya predetermined center and said shank having an upper forward attachingportion, a frame for supporting said tool, and means for securing theattaching portion of said shank to said frame against vertical movementrelative thereto at spaced points between which the attaching portion ofsaid shank is free to flex, the ratio of the curved portion of saidshank below the horizontal plane of said center to the portion of saidshank between said plane and said securing means being Within the rangefrom about 2:5 to about 2:8 so that when said earth-working elementencounters resistance tending to oppose its forward movement, thetendency of the curved portion of the shank to increase its radius ofcurvature and cause said earth-working element to move downwardly isapproximately compensated for the tendency of the portion of said shankbetween said plane and said securing means to flex upwardly.

10. An earth-working implement comprising an earthworking tool having aresilient shank adapted to have an earth-working element fixed to thelower end thereof, the lower portion of said shank being curveddownwardly and forwardly approximately about an are having approximatelya predetermined center, said shank above said lower portion being curvedsubstantially in an arc of a circle of greater radius than saidfirst-named arc with its center located approximately in the horizontalplane of said first-named center, said shank forwardly of the last-namedcurved portion thereof having a straight attaching portion, a supportingframe, and means for securing said straight portion of said shank tosaid frame at spaced points against vertical movement nelative to saidframe, said straight portion of said shank be tween said spaced pointsbeing free to flex. downwardly.

11. An agricultural implement comprising an earthworking tool having aresilient shank adapted to have an earth-working element fixed to thelower end thereof,

ovement relative to such member, said the lower portion of said shankbeing curved downwardly and forwardly for connection to such an element,said shank having an upper forwardly extending, attaching portion, andmeans for supporting said attaching portion comprising'an' invertedV-shaped frame extending transversely of the direction of movement ofthe implement, said frame having a downwardly and rearwardly extendingflange and a downwardly and forwardly extending flange, bracket meansconnected to said frame, and securing means connected to said bracketmeans for securing the forward end of said attaching portion rigidlywith respect to said bracket, said supporting means rearwardly of saidsecuring means having a portion forming a bearing for the attachingportion of said shank to fix said'shank at said bearing against verticalmovement while permitting lengthwise slidingmovement of said attachingportion; said attaching portion between said bearing and said securingmeans being free to flex.

12. Apparatus constructed in accordance with claim 11 wherein saidbearing has a normal line of contact with said attaching portionrearwardly of which line said bearing curves upwardly and rearwardlywhereby, when said shank rearwardly of said bearing is flexed upwardly,said line of contact moves slightly rearwardly and transmits forces tosaid downwardly and rearwardly extending flange at a more acute anglerelative thereto.

l3."Apparatus constructed in accordance with claim 11 wherein saidsecuring means comprises a bolt and said bracket means has spaceddepending ears between which the attaching portion of said shank isarranged,

said ears being provided with rearwardly and upwardly slopingslotsreceiving said bolt, said bolt being connected to the attachingportion of said shank and being fixable in said slots by tightening saidbolt.

References Cited in the file of this patent UNITED STATES PATENTS Ryder"May 10, 1892 748,466 Bateman Dec. 29, 1903 1,830,013 Bohmker Nov. 3,1931 2,029,249 Noell etal. Jan. 28, 1936 2,195,631 Post et al; Apr. 2,1940 2,385,950 Silver Oct. 2, 1945 2,464,615 Sawall Mar. 15, 1949FOREIGN PATENTS 560,161 Germany Sept. 29, 1932

